Last category of anti-vibration technique is a single-shot interferometer with spatial phase shifting.
Phase shifting is necessary to enhance measurement accuracy and this is accomplished spatially as opposed to temporal phase shifting techniques.
Smythe and Moore [1]} used polarization beam splitters and waveplates to acquire 4 phase-shifted fringes.
Millerd et al. [2]} used holographic elements and polarizers to obtain 4 phase-shifted fringe.
Pixelated phase-mask can also be used for spatial phase shifting [3]}.
Spatial carrier phase shifting technique is widely used due to its simple and easy embodiment [4]}.
By introducing linear tilt phase term in reference or test beam, a spatially modulated fringe can be obtained and analyzed with several algorithms such as sinusoidal fitting [5]} and Fourier analysis [6]}.
